Friends, colleagues, fellow scientists of the pump:

For the past two years, I have traveled to 14 gyms across 3 continents, performing an identical pump protocol at each location, and recording my Perceived Pump Intensity (PPI) on a 1–10 scale. My goal was simple: does altitude affect the pump?

I quit my job for this. I sold my car. My girlfriend left me somewhere around gym #8 (Nairobi, 1,795m). I regret nothing. The data demanded collection and I was the only one willing to collect it.

Here are my results:

Correlation between altitude and PPI: r=0.71

This is not nothing. But I must be honest: the findings are inconclusive. The correlation exists but there are confounding variables I could not control for — jet lag, diet changes, emotional state (particularly around gym #6-7), equipment differences, and the fact that by gym #11 I had not slept properly in three weeks and was surviving on instant noodles and determination.

But the data whispers. At altitude, the pump is different. It is more. I felt it in Lhasa. I felt it in La Paz. Something happens when you pump above 3,000 meters. I cannot prove it yet. But I have 14 data points and a ruined life, and I believe that counts for something.

Hans. Brother. I need to address some things.

First: you quit your job, sold your car, lost your girlfriend, and traveled to 14 gyms to determine if altitude affects the pump. This is either the most dedicated pump research in history or a mental health crisis documented in spreadsheet form. Possibly both. I respect it either way.

Second: your data has a fundamental problem. You performed 4 sessions in Lhasa and 12 sessions in Amsterdam. That is a 3x difference in sample size between your highest and lowest altitude points. The Lhasa PPI of 8.1 is based on four workouts. I have had four bad workouts in a single week. Four data points is not a finding. It is a long weekend.

Third: you described the Lhasa pump as occurring while "lightheaded." Brother, that is hypoxia. You were not experiencing an enhanced pump. You were experiencing reduced oxygen saturation at 3,650 meters above sea level. The "otherworldly" feeling in La Paz was altitude sickness. The "spiritual" pump in Addis Ababa was your body struggling to oxygenate your muscles. You didn't discover altitude-enhanced pumping. You discovered that it's hard to breathe on mountains.

That said: the r=0.71 is interesting and I cannot fully explain it with hypoxia alone. The mid-altitude data points (Zermatt, Nairobi, Kathmandu) show a consistent elevation in PPI that precedes the altitude where hypoxia typically manifests. Something might be there. I just don't think it's what you think it is.

I considered this. I considered it extensively, in fact, while sitting in a hostel in Kathmandu at 2 AM unable to sleep because of the altitude and also because of the implications of my data.

You are correct that the Lhasa and La Paz data points may be confounded by hypoxia. I acknowledge this. But I want to draw your attention to the mid-altitude band, specifically gyms #3, #6, #7, and #10 (Zermatt, Nairobi, Addis Ababa, Kathmandu), all between 1,400–2,355 meters. These are altitudes where hypoxia is minimal in acclimatized individuals. And yet the PPI scores are consistently elevated: 7.4, 7.6, 7.8, 7.5. All above baseline.

Something is happening at moderate altitude that is not explained by oxygen deprivation. I hypothesize it is related to reduced barometric pressure affecting blood vessel compliance, resulting in a more efficient vasodilatory response during resistance exercise. In plain language: at moderate altitude, the blood vessels open more easily, and the pump comes faster and fuller.

I cannot prove this. I have 14 data points and a PPI scale I invented. But the mid-altitude signal is real, and I will continue to investigate it, assuming my savings last, which they will not.

Regarding my girlfriend: she has blocked my number. I believe this is unrelated to the altitude research but the timing is suspicious.

Formal review follows.

Recommendation: REVISE AND RESUBMIT. The data is insufficient but the question is good. Pump at more altitudes. Bring a blood pressure cuff next time. And a therapist.

This is the most accurate description of my research methodology I have ever read, and I will be citing it in my revised paper.

I accept the review. I will revise and resubmit. I have already identified 8 additional gyms at altitudes between 800–2,000 meters that I can reach by bus (I no longer have a car). I will bring a blood pressure cuff. I will develop proper anchors for the PPI scale. I will not bring a therapist because I cannot afford one, but I will journal my emotional state, which I have been told is therapeutically equivalent by someone on a different forum.

The mid-altitude band is real. I felt it. The data supports it, weakly but consistently. And I would rather be a man with 14 data points and a ruined life who was right about the pump than a man with a stable career and a girlfriend who never asked the question.

I will return with more data. I am currently in La Paz. The pump here is extraordinary. The altitude is 3,640 meters. The air is thin. My wallet is thinner. But the pump is thick, and that is what matters.